The present invention generally relates to an implantable tube or cable, such as a lead cable, for use with a medical device, and more particularly relates to an anchor for securing the tube or cable to the surrounding tissue.
A variety of devices exist which make use of cables or tubes for delivering electrical signals, fluids, etc. from a medical device to a region of the body, or simply for holding device(s) in place. For example, electrical lead cables, i.e., leads or lead extensions, that detachably connect to an electrical device or to other lead cables may deliver electrical stimulation to a nerve, muscle, or other tissue. For instance, numerous medical devices, such as neural stimulation devices, cardiac pacemakers, and defibrillators, commonly establish a connection between an implanted lead or lead extension (both will be referred to herein as lead cables or simply leads) and an implanted electronic package. In a typical pacemaker, the proximal end of a lead may be removably connected to a lead extension, which in turn is removably connected to an implantable pulse generator. The distal end of the lead, containing one or more electrodes, is typically inserted in or on the heart.
The most effective position of the electrodes or other devices at and/or along the distal end of the lead is commonly determined during surgery. Once the lead is implanted in this preferred position, it needs to be secured to surrounding tissue to prevent it from becoming dislodged. Accordingly, a lead anchor (also referred to as a suture sleeve) that surrounds or is a part of a lead cable may be provided. The lead anchor may require the physician to use, for instance, suture material to secure the anchor to the lead cable. Generally, lead anchors are configured to allow a physician to wrap suture(s) around and/or through the lead anchor multiple times, while securing the sutures to the adjacent tissue.
While securing the lead anchor to the lead cable and while securing the anchor (and thus the lead) to the adjacent tissue, a common problem is over-tightening of the sutures. The stresses resulting from over-tightening can damage the wires within the lead cable and/or break the insulation, which may ultimately cause the lead to fail. Thus, the lead anchor configuration preferably reduces the opportunities for such lead damage.
Securing the lead in place should be simple, to reduce surgical time, and evident, to limit chances for error. The lead anchor is preferably slidable along the lead so it may be positioned appropriately for different implant locations and for a variety of patient body types. Multiple lead anchors per lead cable may be useful in some situations.
The lead anchor is preferably compact and light-weight, and constructed of biocompatible materials. Once properly secured, the connection between the anchor and lead cable should be strong enough to resist pulling and any other forces that could unintentionally disconnect the lead cable from the surrounding tissue.
There exists a need in the art for a compact, easy to operate, fast, and reliable way to secure a tube or cable, such as a lead cable, to surrounding tissue that limits the likelihood of damage to the tube or cable.
The present invention addresses the above and other needs by providing an anchor for securing lead cables, i.e., leads or lead extensions, or other cables or tubular members within a body. The device of the present invention preferably applies to a lead with electrodes at one end of the lead. The other end of the lead is typically detachably connected to a lead extension. Alternatively, the invention applies to the lead extension that is typically detachably connected to the lead at one end and to a medical device at the other end. Furthermore, the invention may apply to any conduit, cable, tube, or other elongated, cylindrical member that is to be secured in a body.
The lead anchor of the present invention preferably comprises two coaxially arranged sleeves and a coaxial spring. The sleeves preferably include suture holes that allow the anchor to be secured to the surrounding tissue. A channel is preferably provided in each sleeve, allowing the spring to be secured at one end to one sleeve and at the other end to the second sleeve. The sleeves also include a locking mechanism that holds the sleeves in at least one, but preferably in two or more positions relative to each other. The locking mechanism preferably comprises a protrusion on and/or in one sleeve that fits into one of two or more recesses on and/or in the other sleeve. As the sleeves are rotated in relation to each other, the protrusion settles into one or the other of these recesses.
As one sleeve is rotated in relation to the other, the spring is also twisted, which causes the inner diameter of the spring to increase or decrease. The locking mechanism thus holds the spring in one of a variety of positions with one of a variety of inner diameters. For instance, by rotating one sleeve until the protrusion fits into one of the recesses, the spring is held in a position that releases the lead cable. Rotating the sleeve in the other direction causes the inner diameter of the spring to decrease, which in turn causes the spring to grip the lead cable. The sleeves may be locked into this position with the protrusion settled into a different recess. Once locked in this position, the lead anchor may be secured to the surrounding tissue.
Thus, the present invention allows easy locking and unlocking of the anchor onto the lead cable without a need for sutures. Anther advantage, inter alia, of the lead anchor of the present invention is its simple design, and its small size. The lead anchor may be activated with fingers or with tools. Improved control and load distribution result from some embodiments of the invention. The simple and sure mechanism of the present invention thus results in reduced surgical time and possible error, while ensuring a secure hold between the anchor and lead cable, and to the surrounding tissue.